import { createApp } from 'vue'
import App from './App.vue'
import router from './router'
import store from './store'
//1.引入element-plus组件库与其样式
import ElementPlus,{ElMessage} from 'element-plus'
import 'element-plus/dist/index.css'
//2.引入element-plus图标库,并起别名为ElementPlusIconsVue
import * as ElementPlusIconsVue from '@element-plus/icons-vue'
//6.1修改elementPlus默认中文
import zhCn from 'element-plus/dist/locale/zh-cn.mjs'

//10.1 配置后端服务器的根路径
const BASE_URL='http://localhost:8080';
//window对象时浏览器内置的全局对象,给他设置的属性就是全局属性，可以在任意的script标签中使用
window.Base_URL=BASE_URL;

const app = createApp(App)/* 创建vue实例,并起名为app */
//3.将所有导入的图标组件变为键值对数组,并依次遍历取出每一个图标组件[key, component]
for (const [key, component] of Object.entries(ElementPlusIconsVue)) {
    // 4.将当前遍历到的图标组件注册为当前vue实例的全局组件
    app.component(key, component)
}
//5.为前vue实例应用element-plus组件库
//6.2 app.use(ElementPlus,{ locale: zhCn })将El本地化为中文
app.use(ElementPlus,{ locale: zhCn }).use(store).use(router).mount('#app')

//7.解决ResizeObserver Error
const debounce = (fn, delay) => {
    let timer = null;
    return function () {
        let context = this;
        let args = arguments;
        clearTimeout(timer);
        timer = setTimeout(function () {
            fn.apply(context, args);
        }, delay);
    }
}
const _ResizeObserver = window.ResizeObserver;
window.ResizeObserver = class ResizeObserver extends _ResizeObserver {
    constructor(callback) {
        callback = debounce(callback, 16);
        super(callback);
    }
}

//8.定义全局方法，获取当前登录的用户数据
window.getUser =()=>{
    return localStorage.user ? JSON.parse(localStorage.user) : null;
}

//9.配置路由守卫
//to 即将要去的目标路由
//from 当前的路由
//next 是放行函数,调用next()才能进入到目标路由to
router.beforeEach((to,from,next)=>{
    //获取当前登录的用户数据
    let user=localStorage.user;
    //登录了，就放行，没登录就提示用户并跳转至登录页
    if (to.path!=='/login'&& !user){
        next({path: '/login'},ElMessage.error('请先登录'))
    }else {
        next();
    }
})
















